My question is the same as the title. Inputting special characters like à, ï, ê by long pressing the key and using space to choose is really convenient. So, does anyone knows if there’s a similar tool on Linux? Or, can Poweraccent be implanted to KDE?
Indeed, the compose key is the currently supported way to do this. We did at one point try out a thing like what you’re asking for, and it got all the way implemented, but ended up being abandoned because it wasn’t implemented in a way that was scalable, stable, or sustainable, and the process of building it exposed fundamental flaws in the way input methods are handled that needed to be fixed first. And unfortunately, that never ended up happening.